2007 barely escapes being Atlanta’s driest year ever
The driest year on record for the city of Atlanta was in 1931, with a total of 29.14 inches. With the recent rain, Atlanta is now at a total of 29.27 inches for the year.
Even better, the short-term forecast is looking pretty good, with north Georgia possibly getting 3-4 inches of rain in the next five days. That certainly won’t solve our problems, but every little bit helps.
The Lawrenceville Weather Blog has the full details.
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December 26th, 2007 at 8:24 am
Boy, I come back from Christmas to find the lake has been going UP, not down. It’s down all of 0.02 in the last five days. Nice.
December 26th, 2007 at 11:00 am
It’s a good sign. But – like I said in an earlier post, now is when the lake should start rising up to it’s peak in the spring. The lake will need to rise around 18 feet to get back to where it peaked last spring. I don’t see that happening with the most optimistic winter rain predictions. Even if we rise ten feet which is what I am hoping for – we will be starting the summer off in a bad position.
December 26th, 2007 at 12:57 pm
I was just commenting that I was pleasantly surprised to see the drop had been so small over the holiday RichS, not making a prediction based on four days of data. It’s not a sign, good or bad – it’s just dumb luck.
RichS, you have to realize that a 10 foot gain is a pipe dream. I looked back at the last decade of water gain from January 1st through June 1st:
1997 – 5.5 feet
1998 – 4 feet
1999 – 5.5 feet
2000 – 5 feet
2001 – 6.5 feet
2002 – 7 feet
2003 – 3 feet
2004 – 2 feet
2005 – 1.5 feet
2006 – LOSS of 1 foot
2007 – 4 feet
20 feet is basically impossible. 10 feet, maybe in a rare, truely wet winter and spring. But during a historic drought?
Barring some significant change in the way water is released from Buford Dam, or a freak change in weather patterns, there will be no “spring peak”. If you’re lucky, there won’t be much of a drop. I doubt there will be a gain.
I wish you were right. But the math doesn’t agree with you.
December 26th, 2007 at 1:49 pm
I have some better numbers, which you may like RichS –
In the last 30 years, the average gain from Jan 1 through June 1 was 4.75 feet.
However, during 15 of those years the elevation on Jan 1 was under 1066 feet; I took that to mean the ACE would deliberately try to keep MORE water in the lake, which is similar to our situation now. The average then? 7.51 feet.
And 7 of those last 30 years the elevation on Jan 1 was below 1060 feet, and I assumed that would mean the ACE was trying desperately to keep water in the Lake. The average? 9.65 feet.
So, I revise my position. A gain is likely given past water conservation efforts in the lake by the ACE during periods of extremely low lake levels. Further, historically, the largest elevation gains have occurred when the lake has been at it’s lowest point.
As bizarre as it may sound, 10 feet is not out of the question, but still not likely, given past data.
December 26th, 2007 at 4:08 pm
Part of the reason that the normal rise is only several feet during the spring is because on average on Jan 1 the lake level is only 6 feet below the top of conservation, and the ACE keeps it from going above that level if possible to preserve flooding protection, so there is a limit to how much it can rise. Thus said, no way it’s going up 10 feet this winter….
December 27th, 2007 at 9:39 am
Paul stole my thunder – yes, if the lake only needs to go up a couple of feet to hit full pool that is all it will go up. Then releases will increase. So the data is only good when you are starting with a low lake level. For instance when you look at data like the 2006 loss of one foot you have to remember you were starting at full pool. And I will point out that I am not projecting a ten foot rise. I have used the ten foot figure as a number I am hoping for – best case.
I would like to also point out that a ten foot rise now would be equivalent to a much smaller rise at full pool. It has been very well documented here by rkolter and others that the lake sides are not vertical. So maybe a ten foot rise now is equivalent to a seven foot rise at full pool? Maybe less? That starts to sound plausible huh??? Maybe not likely – but certainly plausible.
December 27th, 2007 at 11:01 am
I’ve put some more effort into the math here – looking at the last 48 years of data (ignoring the first three years when the lake was filling), there is a very clear trend that the lower the lake is on January 1st, the more it will fill by June 1st – this takes into account previous drought conditions as well.
There are however, a few exception years where despite a low lake, water levels didn’t rise significantly, or as significantly as they did in other years with similar low lake levels. There is also one year on record where the lake started out low (below 1065 feet) and actually lost water by June-1. So, this -is- possible.
My gut says the lake elevation should decline. The math doesn’t back up that up though. So let me tell you what the math DOES say:
Every single 10′ gain from Jan-1 to June-1 has occurred when the lake has been below 1061 feet.
The lake has gained elevation during that period in every single year on record save three, and two of those three were when the lake started at over 1068 feet to begin with (the assumption being that the ACE was releasing water quickly to avoid going over Full Level).
All the significant elevation gains have occurred when the lake was at 1065 feet or below on Jan-1.
The average gain when the lake has been below 1062 feet, is just over 10 feet of elevation.
I am going to go with the math and predict a moderate rise in level from today’s level, by June-1. Between now and then it may vary, but in the end, I suspect it will rise. I will peg my guess at 5.5 feet, which falls within the midrange.
December 27th, 2007 at 11:33 am
rkolter said: “Every single 10′ gain from Jan-1 to June-1 has occurred when the lake has been below 1061 feet.”
You’re ignoring the fact that it’s impossible to rise 10′ if the lake was at 1065. 1065 + 10 ft = 1075 which is four feet above full pool.
It’s a simple fact that if the lake is lower, it will fill more because there is more room for it to reach full pool. This year is especially unique because of the drought conditions so it probably won’t rise a significant amount, if any.
December 27th, 2007 at 11:43 am
Also, a question for rkolter – if you’re reviewing the last 48 years worth of data for the lake levels, are you correlating that with any rainfall data? It seems like it would be important to know how much rain fell for each of those years.
If 2007 was the second driest year on record (and the driest year since Lanier existed) then things are going to be quite different in 08….
December 27th, 2007 at 12:30 pm
CrazyD – I’ve ignored nothing. It is not impossible for the lake to rise 10′ from 1065 feet; the full pool may be at 1071 feet, but the lake has 14 more feet to go before you risk overflow – this is the flood control level. But, as Paul, Rich, and I have all said, the ACE does release more water to control the level when the lake is high to begin with, to conserve that flood control level.
So it is not that a 10′ rise is impossible during a year that starts with a high lake, but that the ACE doesn’t allow a 10′ rise during that year. Which is fine – the salient point is that during a dry year with a low lake, the ACE is still able to allow several additional feet of water to flow into, and remain in, Lake Lanier.
Which brings me to the rainfall question – Rainfall during the current month or year does not necessarily correlate to Spring Peak size. You give 2007 as an example – 2007 was the second driest year, but only the 13th lowest Jan-1 data point (1061.56 feet), and yet the 10th HIGHEST Spring Peak (gain of 8.95 feet).
You’re right that 08 will be different though, in that it will be the lowest Jan-1 data point ever. The point I’ve made is that the math shows the lower the Jan-1 data point, generally the higher the elevation gain by June-1, even in a drought.
Ergo statistially, the potential for a gain by June-1.
December 27th, 2007 at 12:59 pm
I would like to reiterate my initial point which was that I get the sense there are quite a few people who believe if the lake isn’t falling the problem isn’t getting any worse. The truth is that if the lake doesn’t rise considerably by spring, the problem will be getting worse. You can get a sense of that by looking at the forecast chart that I have linked before.
http://water.sam.usace.army.mil/lanfc.htm
If you look at the line for action level four which could be considered extremely low lake levels, that baseline rises considerably (approx 10 feet) through January and February. If we lose ground with respect to that baseline, I would argue that our position has worsened.
December 27th, 2007 at 4:06 pm
Don’t take it personally, but I think it’s a totally worthless point to make since your entire calculations are based on an unknown variable – which is how much ACE released to keep the level at full pool without going over. You stated yourself that ACE releases more water when the lake is high to preserve flood control levels. If the lake started at a high level and ACE didn’t release water then maybe it would’ve risen 15 feet. That’s something you don’t know; therefore, you cannot say the rise was highest when the Jan 1 starting levels were lowest.
And my rainfall point was to wait and see what rainfall occurs Jan-1 to Jun-1. I know 2007 won’t directly correlate to 08 spring peak size, but with the amount of rainfall heading into 2008 it doesn’t look too great.
How much rainfall occurred during the Jan-1 to Jun-1 2007 time frame which led to the gain of 8.95 feet? That seems like something worth looking at….
December 27th, 2007 at 5:02 pm
The daily average rainfall for January 1 to June 1 2007 is as follows
Jan – .08
Feb – .07
Mar – .06
Apr – .05
May – 0.00
The daily average rainfall for January 1 to June 1, 2006 was:
Jan – .13
Feb – .10
Mar – .05
Apr – .06
May – .05
The daily average rainfall for January 1 to June 1, 2005 was:
Jan – .05
Feb – .13
Mar – .10
Apr – .08
May – .03
If you want to see the actual daily amounts you can find them at :
http://water.sam.usace.army.mil/gage/bufrain.htm
What we could do is create a spread sheet taking the data from those pages for lets say the last 5 years (just an example) and compare that to the date for daily outflow amounts found at:
http://water.sam.usace.army.mil/gage/bufout.htm
Of course the farther back we take it the better the data will be and it might give us somewhat of an idea what to expect but it’s still going to be a “best guess” type of situation. If we could also factor in inflow, outflow and rainfall amount for the lower dams along the river that might give us an even better picture.
December 27th, 2007 at 5:06 pm
CrazyD – I actually don’t just pull numbers out of thin air.
I do have rainfall numbers. I do have ACE release numbers. By day, avergaged by Month. It’s a lot of data. You keep insisting that I don’t have it. I also have the ACE releases, day by day, month by month, for those months and those years. And for the months and years of high elevation.
You are correct, I don’t have water numbers for releases during years of plenty of water in the Lake. The trend line is valid, in that it does show that the ACE controls the level of the lake carefully by adjusting it’s releases, and that’s backed up by release data from the ACE.
Still, I should rephrase:
“During periods of drought and low rainfall, when the lake comes out of the year at 1060 or lower, it still very often manages a 10 foot or better gain in depth due to the efforts of the ACE to allow the lake to refill. At worst, it managed almost 5 feet. On average, it manages just a shade over 10 feet. In any case, It has never failed to gain water, even during droughts that were at the time considered epic.”
It’s important to note that while this drought is huge and the lake has never been this low, it isn’t so bad a drought that previous droughts we have data on pale in comparison. It is still ok to use previous drought data to forecast how the lake will react in this drought.
December 27th, 2007 at 5:25 pm
I think rephrasing your statement makes it a lot more clear and accurate. It also raises the intriguing question of how much rain fell during the 5 month period for the lake to rise 10 ft?
Out of curiosity, can you tell me what the total rainfall amount for Jan, Feb Mar, April and May of 07 were? Or point me to where I can find this information if it’s already online.
December 27th, 2007 at 5:30 pm
Rkolter – I’m a short timer living on the lake, but I haven’t seen it go over full pool. I know it can and probably does, but I think they pretty much release everything once it hits full pool unless maybe they need to control flooding downstream. It has been widely discussed – though I haven’t seen it on this forum that full pool should be raised one or two feet to increase storage capacity.
December 27th, 2007 at 5:43 pm
rkolter,
Have you been looking at the old data from the reservoirs downstream? I know that ACE has stated that since they are more or less empty, they have been using Lanier almost solely to regulate downstream flow. It would be interesting to see if during the prior “epic droughts” if those reservoirs were empty, as that could be a difference that the ACE would have to take into account with their “efforts to allow the lake to refill”. I haven’t looked at the data at all, just a question.
In related news, La Nina is still going strong.
http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomp.12.27.2007.gif
December 28th, 2007 at 9:09 am
Paul – You make a really good point and it is something I had NOT considered. I am going on the assumption that a prior drought of any significance will affect the resevoirs similarly to the current drought. But, I don’t have that data at my fingertips. I will point out the downstream resevoirs aren’t all empty, and downstream flow is being regulated by the West Point dam, not Lanier.
RichS – Sorry, I think you misunderstood me – CrazyD had said that it was impossible for the lake to rise 10 feet from 1065 elevation. I was disputing that. I didn’t mean to imply that the lake ever regularly went much over Full Pool, only that Full Pool wasn’t the real maximum capacity of the lake or of Buford dam.
CrazyD – Glad to offer up the data! This is the site that I think most of us data geeks are pulling from:
http://water.sam.usace.army.mil/gage/acfhist.htm
A note though – They use a “Lanier Year”, which is for some burocratic reason, October through September. So if you wanted for example, all of 2007′s data, you would pull January through September from 2007, and October through December from 2008.
There are other great resources online, including a huge data dump available from J.C. Wren, who runs this site: http://tinymicros.com/lanier/ and who reads these blogs as well.
Rainfall data in particular goes back to 1995. I’ve seen earlier data, and a 100 year average data by month, but I’ve lost those links. :/
December 28th, 2007 at 9:25 am
Rain is coming down hard in Gainesville. I saw water standing in the street on my way in to work. If this keeps up we could see some nice accumulation today.
December 28th, 2007 at 9:30 am
Well, this is vaguely frustrating. I can post in other blog entries, but the entry I want to post to this blog entry is being kebashed. I’m seeing other entries appear, and when I try to post, it says I have a duplicate post.
So if we see a dozen similar posts from me suddenly show up, I appologize in advance.
December 28th, 2007 at 9:31 am
… and no magically there it is – it just appeared above RichS’s entry about Gainsville rainfall, despite me having seen that for several minutes without my post.
Oh well. Nevermind this post, and the one just above it!
December 28th, 2007 at 9:34 am
Sorry about that — it was some issues with the spam filter.
If any of you post something and it doesn’t appear, shoot me an e-mail (info@atlantawatershortage.com) and I’ll dig it out of there.
December 28th, 2007 at 9:43 am
Record Drought Far From Over
Jackson County has already completed an analysis of its future water needs and of locations for potential reservoirs. None of those solutions could be employed to alleviate the current drought, but just as the drought of 1986 led to the construction of the regional reservoir, the drought of 2007-08 will likely be the catalyst for building new reservoirs and implementing water conservation areas.
“It’s a learning experience,” Bell notes.
December 28th, 2007 at 11:42 am
Just in case there is any confusion – the posting above is all Oconee basin water which is of course imporatant in itself but separate from the ACF basin that this forum is primarily talking about.
December 28th, 2007 at 2:04 pm
This is the average rainfall for Atlanta.
3” is a weeks time for December would be significant considered the monthly average is 3.8”.
Keep in mind also that the minimum flow rate for Lanier has not changed since the dam was built.
http://www.rssweather.com/climate/Georgia/Atlanta/
Month Precipitation for Atlanta
Jan 5.02in.
Feb 4.68in.
Mar 5.38in.
Apr 3.62in.
May 3.95in.
Jun 3.63in.
Jul 5.12in.
Aug 3.67in.
Sept 4.09in.
Oct 3.11in.
Nov 4.10in.
Dec 3.82in.
December 28th, 2007 at 2:56 pm
JohnC – Can you clarify your statement “Keep in mind also that the minimum flow rate for Lanier has not changed since the dam was built. ”
I’m actually not arguing (yet). I’m just not sure what you are saying. Right now, the minimum flow that we generally talk about is the 5000 cfm rate at the mouth of the Apalachicola River. But I don’t think that is what you are talking about – I wouldn’t call it a flow rate for “Lanier”, and it is the product of a fairly recent agreement between the three states so I’m not sure how you could say it hasn’t changed since the dam was built. If you are talking about a different flow rate figure can you please point to some data or clarify?
December 28th, 2007 at 4:18 pm
At 8:15 am Lake Lanier was at 1050.72. At 3 PM it was up to 1050.89.
December 28th, 2007 at 4:24 pm
Wspurlock – Did they release during that time? I would have hoped for a little more rise if they didn’t. We had a really good soaking this morning on the north end of the lake.
December 28th, 2007 at 4:55 pm
Nope, release was early this morning. As it flows downstream into Lake Lanier we should see it go up somewhat more. And it looks like once again more rain fell to the south of us so we should see further reduced releases for the next few days which added to the increase coming into Lanier from above it due to this rain we should see better numbers at least on a temporary basis.
December 28th, 2007 at 9:35 pm
RichS,
No problem. My point was that the minimum flow rates have not increased, so that is not why the lake is at record lows.
I was posing the link to the average rainfall for the logic of the thread at hand.
Of course there was the most recent reduction, which was an emergency measure Fl is challenging.
I would like to learn more about the minimum flow rates myself and was only adding what I read.
Good stuff guys!
December 29th, 2007 at 1:53 pm
Yeah, this is really good news wspurlock. Look at that growth! First rise of that amount in a very, very long time.
December 29th, 2007 at 2:29 pm
Any idea HOW long it’s been? Exact date? I’d like to post something about it.
Also, do any of you care to write up a guest post (or even part of one) about the rise we’re expecting (hoping for?) over the next few months? I’ve seen a lot of discussion about it and I was hoping one of you could summarize some of that into something I could post on the blog.
December 29th, 2007 at 4:18 pm
It seems that the midnight pool numbers are whats used as the official numbers, so I’ll go with those.
December 28 – 1050.79
December 29 – 1050.88
This appears to be the largest gain in one 24 hour period (midnight to midnight) since March 1 – 2 of this year:
March 16 – 1068.14
March 17 – 1068.23
December 29th, 2007 at 4:24 pm
However, it looks like it’s a safe bet that we will see a slightly larger gain for today. At 3 pm we were back up to 1051.00 with the daily release still to come this evening.
December 31st, 2007 at 10:52 am
Rkolter – Going way back up to your math at the top of this string, I will also point out that June 1st isn’t necessarily the peak of the lake levels. You show a four foot gain last spring, but the lake had already dropped two feet off of it’s peak by June 1st. If you used the actual peak last spring you would have come up with more like six feet. And that was during the drought. So we do certainly have hope for significant recharge during the winter / spring.
I think my difference with some others on this forum is that if we got say eight feet of recharge, I would consider that the problem has gotten worse not better. I would consider a ten foot gain to be basically breaking even – just buying time for the drought to hopefully break.
December 31st, 2007 at 5:58 pm
There should not be so much water released down stream until the water is back to normal. No there were no releases because of mangling by alabama’s gov
January 2nd, 2008 at 11:42 am
Mickey – Yes, I’d be willing to do a guest post about it. I’ve put my best guess up in the predictions page too. Let me write something up, may take a couple days.
January 2nd, 2008 at 1:13 pm
Great! Just e-mail it to me when it’s ready. Thanks.
January 2nd, 2008 at 5:50 pm
Dr. Jeff Masters has an article on what caused the drought and what to expect in the future on his blog:
http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=886&tstamp=200801